With the constant progress of light-emitting diode technology, white-light light-emitting diodes witness declining prices and shrinking profits. Therefore, the market tends to seek for new and special applications, in particular, applications of the infrared light-emitting diodes among invisible light-emitting diodes. Infrared light-emitting diodes, due to advanced technology and high technical threshold, are much more profitable than white-light light-emitting diodes. Infrared light-emitting diodes are mainly applied in remote control and safety control, also in various image, somatosensory and position sensing applications.